Lighting: Bright Idea

ULTRA LIGHT: Philips' new lamps use clusters of highly efficient lightemitting diodes and should last up to 20 years

The next time you flick on a light switch, consider this: about one-fifth of the world's electricity is used for lighting, and most of it is squandered. Traditional incandescent light bulbs invented more than a century ago remain the norm, but they are horribly inefficient. Only about 5%-10% of the energy they consume is used to produce light, while the rest is burned off as useless heat.

For Allard Bijlsma, that spells opportunity. Standing in a conference room in a suburb of Antwerp, he picks up an oblong silver object slightly smaller than a rugby ball, brandishes...